Cutaneous anthrax

– Anthrax is caused by the bacterium Bacillus anthracis that primarily affects herbivores (sheep, goats, cows, camels, horses, etc.). Humans may become infected through contact of broken skin with a dead or sick animal. People at risk include livestock farmers and those that manipulate skins, wool or carcasses of infected animals.
– The disease is found in Eastern Europe, Central Asia, the Mediterranean Basin, Africa and South America.
– Pulmonary (acquired by inhalation) and intestinal (acquired by eating infected meat) forms also exist.

Clinical features

– Papule, then pruritic vesicle on uncovered skin surfaces (face, neck, arms, legs). The vesicle ulcerates and becomes a painless black eschar surrounded by oedema, often associated with with lymphangitis and regional lymphadenopathy.

– The following are criteria of severity:
• lesion located on the head or neck, or
• presence of systemic symptoms (fever, malaise, headache, tachycardia, tachypnoea, hypotension, hyper/hypothermia), or
• presence of extensive oedema, or
• multiple, extensive or bullous lesions.


– From vesicular fluid1 : culture and susceptibility testing (rarely available) or Gram stain for microscopic examination.
– PCR testing (reference laboratory).


Uncomplicated cutaneous anthrax 

– Do not excise the eschar; daily dry dressings.
– Antibiotherapy for 7 to 10 days:
• If drug susceptibility is not known:
ciprofloxacin PO is first-line treatment for all patients including pregnant women and children:
Children: 15 mg/kg 2 times daily (max. 1 g daily)
Adults: 500 mg 2 times daily
Alternatives include:
doxycycline PO (except in children under 8 years and pregnant or lactating women)
Children 8 to 12 years: 50 mg 2 times daily
Children over 12 years and adults: 100 mg 2 times daily
clindamycin PO (e.g. in pregnant or lactating women and children less than 8 years)
Children: 10 mg/kg 3 times daily (max. 1800 mg daily)
Adults: 600 mg 3 times daily

• If penicillins are effective (documented susceptibility):
amoxicillin PO
Children: 30 mg/kg 3 times daily
Adults: 1 g 3 times daily

Severe cutaneous anthrax

– Combination antibiotherapy for 14 days:

   Whatever the protocol used, do not mix the two drugs in the same infusion bag (incompatibility).

• If drug susceptibility is not known:
ciprofloxacin IV infusion over 60 minutes2
Children: 10 mg/kg every 8 hours 
Adults: 400 mg every 8 hours 
clindamycin IV infusion over 30 minutes2
Children 1 month and over: 10 to 13 mg/kg every 8 hours (max. 2700 mg daily)
Adults: 900 mg every 8 hours

• If penicillins are effective (documented susceptibility):
ampicillin IV
Children 1 month and over: 50 mg/kg every 6 to 8 hours
Adults: 4 g every 8 hours
clindamycin IV infusion as above.

Change to oral treatment as soon as possible to complete 14 days of treatment with ciprofloxacin + clindamycin or amoxicillin + clindamycin as for cutaneous anthrax without severity criteria.

– Intensive care: symptomatic treatment of shock (see Shock, Chapter 1); tracheostomy and ventilatory support may be necessary.


– Antibiotic prophylaxis in case of known skin exposure: treat for 10 days PO as for cutaneous anthrax without severity criteria.
– Livestock vaccination; burial or burning of animal carcasses.

Ref Notes
1 Samples can be stored (including transport time) for 7 days max. in cold chain (if not available, at a temperature < 30 °C).
2 Dilute each dose of ciprofloxacin or clindamycin in 5 ml/kg of 0.9% sodium chloride or 5% glucose in children less than 20 kg and in a bag of 100 ml of 0.9% sodium chloride or 5% glucose in children above 20 kg and in adults. Administer ciprofloxacin more slowly than clindamycin. [ a b ]